Automatic focusing apparatus for camera

ABSTRACT

An automatic focusing apparatus in a camera is provided in which a winding operation for advancing the film and for charging the shutter does not cause the displacement of a manual focusing member but returns an automatic focusing member only to a charge position, significantly simplifying the operations in manually focused photography as well as in automatically focused photography.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatically or manually focusablecamera, and more particularly to a camera in which an automatic focusingmember is blocked in case of manually focused photography.

2. Description of the Prior Art

An apparatus of this kind is already disclosed in the Japanese PatentLaid-Open No. 44021/1978 entitled "Safety device for automatic focusingapparatus". In such apparatus, automatically focused photography can beconducted by manually operating a charging member thereby places anautomatic focusing member for driving the photographing lens at a chargeposition, and also places a manual focusing member at an automaticfocusing position. When the shutter is released in this state, themanual focusing member is blocked while the automatic focusing member isput into operation. On the other hand, manually focused photography at afocus distance suitably selected by the manual focusing member can beconducted by similarly operating said charging member, blocking saidautomatic focusing member at the charge position but displacing themanual focusing member from the automatic focusing position to a desireddistance within the range from infinity to the shortest focusingdistance of the lens, and releasing the shutter in this state.

However, as a camera generally requires a winding operation foradvancing the photographic film and charging the shutter, there will berequired, in a camera equipped with an apparatus as explained in theforegoing, a winding operation in addition to the manipulation of thecharging member for the automatic focusing apparatus. This renders theautomatic focusing operation rather cumbersome.

On the other hand, if the charging member is linked with the windingoperation for advancing the film and charging the shutter in order toovercome the above-mentioned drawback, the charging member is actuatedwith every winding operation, causing the manual focusing member to bereturned to the automatic focusing position every time. Thus, in case ofmanually focused photography, manipulation of the manual focusing memberafter each winding operation will be required, thus rendering the manualfocusing operation cumbersome.

SUMMARY OF THE INVENTION

Thus, an object of the present invention is to provide an automaticfocusing apparatus for a camera wherein the winding operation foradvancing the film and for charging the shutter does not cause thedisplacement of the manual focusing member but returns only theautomatic focusing member to the charge position, thereby overcoming theabove-mentioned drawbacks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 4 show a first embodiment of the present invention, whereinFIG. 1 is a cross-sectional view of the apparatus of the presentinvention and showing manually focused photographing;

FIG. 2 is a cross-sectional view along the line A--A in FIG. 1 andshowing a state before the start of shutter release;

FIGS. 3A and 3B are developed cross-sectional views along the line B--Bin FIG. 1, and showing the positional relationship of the cam facerespectively in the automatic focusing and in the manual focusing;

FIG. 4 is a developed external view of the manual focusing member; and

FIG. 5 is a view similar to FIG. 2 and showing second and thirdembodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now the present invention will be explained in detail by the followingexplanation to be taken in conjunction with the attached drawings.

In FIGS. 1 to 4 showing an embodiment of the present invention, thecamera body 1 is provided with a fixed member 2 on which there is screwfitted a rotary member 3 so as to be axially displaceable by therotation thereof. There is provided an actuating member 4 having pins4a, 4c, (FIG. 1) a projecting portion 4b and teeth 4d (FIG. 2). Pin 4ais fitted into a groove provided in said rotary member 3 so as to causeintegral rotation of the actuating member 4 and the rotary member 3.Projection portion 4b is adapted to engage a pin 13 brought into aprotruding position in the manually focused photography mode ofoperation, to be explained later. Pin 4c is adapted to engage a releaselink member 5, to be explained later, to block the rotation of theactuating member 4. The automatic focusing members are composed of saidrotary member 3 and the actuating member 4.

The release link member 5, performing a forward movement in connectionwith the shutter release operation and a reverse movement in connectionwith the winding operation, is structured to displace to the right inFIG. 2 by a predetermined stroke (to the phantom line position) inresponse to the shutter release operation. Member 5 disengages from thepin 4c at the start of said displacement and also releases a leadingshutter curtain (not illustrated) upon completion of said displacement.

A manual focusing member 6 comprises in the present embodiment, afocusing ring having thereon a distance scale (FIG. 4), and is provided,as shown in FIGS. 3A and 3B, with a cam face 6a. Cam face 6a ismaintained in contact with a pin 10, which is fixed to a lens supporttube 9, by a spring 11 (FIG. 1). Cam face 6a and pin 10 cooperate todisplace the lens support tube 9 along the optical axis of the lens inresponse to the rotation of said manual focusing member 6. The camerabody 1 is further provided with a fixed outer tube 7 and an inner tube 8screw fitted therewith, said outer tube 7 being provided with a fixedindex mark M as shown in FIG. 4. The fixed pin 10 is fitted into anaxially elongated groove 8a provided in said inner tube 8 and displacestherealong when said lens support tube 9 is axially displaced.

The spring 11 is provided between said inner tube 8 and the lens supporttube 9 to constantly bias said tube 9 towards the camera body 1.

Also provided is a spring 12 between an L-shaped pin 13 and the innertube 8 to constantly bias said pin 13 towards the camera body 1, therebymaintaining the rising or leg portion 13a of said pin 13 in contact witha cam face 6b. Said pin 13 is fitted into an axially extended groove 8bof the inner tube 8 and displaces therealong and also along said camface 6b in response to the rotation of manual focusing member 6.

Actuating member 4 is constantly biased counterclockwise by a spring 14as represented in FIg. 2. The pin 13 engages the projecting portion 4bof the actuating member 4 when the cam face 6b is positioned withrespect to the rising portion 13a of the pin 13 as shown in FIG. 3B.However, when the manual focusing member is rotated to a position asshown in FIG. 3A, pin 13 is moved by cam face 6b to a position where itcannot engage the actuating member. A latch 20 rotatably supported andconstantly biased counterclockwise by a spring 16 is maintained inengagement with the teeth 4d of the actuating member 4, said engagementbeing controlled by a magnet 18 of the automatic focusing unit 17, aswill be described.

The function of the apparatus of the present invention will now beexplained in the following.

(i) Manually focused photography

At first, the manual focusing member 6 is rotated so as to match adesired distance on the distance scale (∞˜1) on the manual focusingmember 6 with the fixed index mark M on the outer tube 7 as shown inFIG. 4. In this state, wherein the distance scale is positioned in frontof the index mark M, the pin 13 is positioned with respect to the manualfocusing member 6 as shown in FIG. 3B and thus protrudes towards thecamera body 1 due to the biasing force of the spring 12. In thisposition, it engages the projecting portion 4b and blocks the movementof the actuating member 4. In this manner the automatic focusing members3, 4 are blocked in this state. When the shutter is released by ashutter release button (not shown), the release link member 5 performs adisplacement to the right (FIG. 2) by a predetermined stroke to release,at the end of said stroke indicated by phantom lines, a leading shuttercurtain (not illustrated) to effect an exposure.

Upon performing a subsequent winding operation, the release link member5 returns to the full-lined original position shown in FIG. 2 to restorethe mechanism to its original state before photographing, illustrated inFIG. 2. During these operation the automatic focusing members 3, 4remain blocked by the pin 13 and the manual focusing member remains inits previously fixed position.

(ii) Automatically focused photography

In this mode the manual focusing member 6 is rotated from the manualfocusing position shown in FIG. 3B so as to match the automatic focusingposition indicated by a mark AF (FIG. 4) on the focusing member with theaforementioned fixed index mark M. This displaces pin 10 to a positionshown in FIG. 3A, and simultaneously moves the lens support tube 9 tothe right-most position shown in FIG. 1, focused at an infinitedistance. At the same time the pin 13 is displaced from the positionshown in FIG. 3B to that shown in FIG. 3A, it is retracted from theorbit of the actuating member 4, thus releasing the automatic focusingmembers 3, 4. However, the actuating member 4 does not rotate in thisstate because of the engagement between the pin 4c and the release linkmember 5. When the shutter is released in this state, the release linkmember 5 performs a rightward displacement as before to thepredetermined stroke position indicated by the phantom lines in FIG. 2.Pin 4c is released at the start of said displacement, allowing theactuating member 4 to rotate counterclockwise due to the biasing forceof the spring 14. Thereupon the rotary member 3, rotating integrallywith the actuating member 4, moves to the left in FIG. 1 to displace thelens support tube 9 in the same direction against the biasing force ofthe spring 11.

Upon detection of the arrival of the lens support tube 9 at a properfocusing position by means of a known mechanism, the automatic focusingcontrol unit 17 deactivates the magnet 18, previously energized,allowing the latch 20 to rotate counterclockwise under the biasing forceof the spring 16 to engage the teeth 4d to block further rotation of theactuating member 4. In this manner the leftward displacement of the lenssupport tube 9 is terminated and automatic focusing is achieved. Uponcompletion of the subsequent displacement of the release link member 5to the right (to the position of the phantom lines in FIG. 2), theleading shutter curtain is released in the same manner as explainedalready in connection with the manually focused photographing.

In response to the winding operation after photographing, the releaselink member 5 performs a return displacement (to the solid position)rotate the actuating member 4 clockwise, by virtue of its engagementwith the pin 4c, against the biasing force of the spring 14, therebyrestoring the mechanism to its state before photographing shown in FIG.2.

Thus, in the foregoing first embodiment, the automatic focusing memberreturns to its original position by the winding operation in case of theautomatically focused photography, i.e. when the index AF is matchedwith the fixed index mark M, so that there will not be required separatemanipulation of the automatic focusing members.

FIG. 5 shows second and third embodiments of the present invention. Insaid second embodiment the mechanical engagement between the projectingportion 4b and the pin 13 is eliminated. Instead, in the manuallyfocused photography mode wherein the distance scale (1˜∞) on the manualfocusing member 6 is matched with the fixed index mark M, a switch 19connected between the magnet 18 and the automatic focusing control unit17 is opened in cooperation with the movement of said manual focusingmember 6 to deactivate the magnet 18, thereby allowing engagementbetween the latch 20 and a tooth 4e on actuating member 4 due to thebiasing force of the spring 16. This blocks the actuating member 4 orthe automatic focusing members 3, 4. In automatically focusedphotography, wherein the index AF is matched with the fixed index markM, said switch 19 is closed in cooperation with the movement of themanual focusing member 6 to energize the magnet 18 thereby releasing thelatch 20 from its engagement with actuating member 4. The shutterreleasing operation and the winding operation are conducted in the samemanner as in the foregoing first embodiment.

In the third embodiment, the switch 19 in the foregoing secondembodiment is replaced by a pin 15 which is laterally displaced incooperation with the movement of the manual focusing member 6 whereby,in case of manually focused photography with the distance scale 1˜∞ ofthe manual focusing member being matched with the fixed index mark M,the latch 20 is caused to engage with tooth 4e by the displacement ofsaid pin 15 toward said latch 20 from the broken-lined position to thefull-lined position in FIG. 5. This blocks the movement of the automaticfocusing members 3, 4, when the shutter is released. In automaticallyfocused photography said pin 15 is retracted in cooperation with themovement of the manual focusing member 6 to release the member 4. Otherfunctions are conducted in the same manner as in the foregoing firstembodiment.

As explained in the foregoing, the present invention, in which thewinding operation does not cause the displacement of the manual focusingmember but returns the automatic focusing member only to the chargeposition, significantly simplifies the operations in manually focusedphotography, as well as in the automatically focused photography.

I claim:
 1. An automatic focusing apparatus for use in a camera forfocusing a photographic lens by axial displacement thereof along theoptical axis of the lens, the camera having winding means for windingfilm and for charging a shutter, and shutter release means for releasingthe shutter to effect an exposure, comprising:a manual focusing membermovable within a predetermined range from a predetermined position;means for coupling the manual focusing member to the lens and fordisplacing the lens along the optical axis for focusing in accordancewith the movement of the manual focusing member within saidpredetermined range; automatic focusing means including an automaticfocusing member coupled to the lens, the automatic focusing memberhaving a charge position and being displaceable from the charge positionin response to the operation of the shutter release means for displacingthe lens along the optical axis for focusing in accordance with thedisplacement of the automatic focusing member; blocking means forblocking movement of the automatic focusing member from the chargeposition except when the manual focusing member is in said predeterminedposition; and means responsive to the operation of the winding means formoving the automatic focusing member from a displaced position to thecharge position, said winding means being ineffective to vary theposition of the manual focusing member.
 2. An apparatus according toclaim 1, wherein said manual focusing member includes signalling means,and said blocking means operates to block said automatic focusing memberin response to said signalling means.
 3. An apparatus according to claim2, wherein said blocking means includes a member capable of engagingsaid automatic focusing member and blocking displacement of saidautomatic focusing member upon said engaging.
 4. An apparatus accordingto claim 2, wherein said signalling means includes cam means capable ofengaging said blocking means.
 5. An apparatus according to claim 1,wherein the blocking means includes a blocking member having a portionengageable with cam means on the manual focusing member and means forbiasing the blocking member into engagement with the cam means, the cammeans being operative to position the blocking member to engage theautomatic focusing member when the manual focusing member is positionedwithin said predetermined range.
 6. An apparatus according to claim 5,wherein the automatic focusing member comprises a ring member having aninternal projecting portion located to engage the blocking member.
 7. Anapparatus according to claim 1 further comprising a movable lens supportwhich supports the photographic lens, and wherein the manual focusingmember is rotatable with respect to the optical axis and the means forcoupling comprises cam means on the rotatable member and pin means onthe movable lens support, engagement between the cam means and the pinmeans being effective to axially displace the lens support in accordancewith the rotation of the rotatable member.
 8. An apparatus according toclaim 1, wherein the automatic focusing means includes detecting meansfor detecting proper focus of the photographic lens, and stop meansoperative in response to said detecting for stopping the displacement ofthe automatic focusing member.
 9. An apparatus according to claim 1,wherein the means responsive to the operation of the winding means formoving the automatic focusing member from a displaced position to thecharge position comprises a link member, the link member being movablein a first direction from a predetermined position in response to theoperation of the shutter release means and being movable in the reversedirection to said predetermined position in response to the operation ofthe winding means, the link member being engageable with the automaticfocusing member when in the predetermined position to hold the automaticfocusing member in said charge position.